def test_repr():
bf = BloomFilter(8000, 3)
assert repr(bf) == "<BloomFilter (length: 8000, hashes: 3)>"
bf = BloomFilter.create_from_capacity(5000, 0.02)
assert repr(bf) == "<BloomFilter (length: 40712, hashes: 5)>"
def test_count_when_full():
length = 8
num_of_hashes = 2
bf = BloomFilter(length, num_of_hashes)
# We index 20 strings to kind of guarantee that
# filter of length 8 is full afterwards.
# NOTE: In perfect situation, only 4 items are required,
# but we don't know which ones.
for i in range(20):
bf.add("test{}".format(i))
assert bf.count() == length / num_of_hashes
def test_init_from_capacity():
bf = BloomFilter.create_from_capacity(5000, 0.02)
assert bf.sizeof() == 5089, "Unexpected size in bytes"
with pytest.raises(ValueError) as excinfo:
bf = BloomFilter.create_from_capacity(5000, 2)
assert str(excinfo.value) == 'Error rate shell be in (0, 1)'
with pytest.raises(ValueError) as excinfo:
bf = BloomFilter.create_from_capacity(0, 0.02)
assert str(excinfo.value) == 'Filter capacity can\'t be 0 or negative'
bf = BloomFilter.create_from_capacity(5000, 0.999)
assert len(bf) == 16
def test_init():
bf = BloomFilter(8000, 3)
assert bf.sizeof() == 1000, "Unexpected size in bytes"
with pytest.raises(ValueError) as excinfo:
bf = BloomFilter(8000, 0)
assert str(excinfo.value) == 'At least one hash function is required'
with pytest.raises(ValueError) as excinfo:
bf = BloomFilter(0, 5)
assert str(excinfo.value) == 'Filter length can\'t be 0 or negative'
def test_len():
bf = BloomFilter(8000, 3)
assert len(bf) == 8000
bf = BloomFilter(8001, 3)
assert len(bf) == 8008
def test_count():
bf = BloomFilter(8000, 3)
assert bf.count() == 0
bf.add("test")
assert bf.count() == 1
bf.add("test")
assert bf.count() == 1
bf.add("test2")
assert bf.count() == 2
def test_lookup():
bf = BloomFilter(8000, 3)
bf.add("test")
assert bf.test("test") == 1, "Can't find recently added element"
assert bf.test("test_test") == 0, "False positive detected"
def test_add():
bf = BloomFilter(8000, 3)
for word in ["test", 1, {"hello": "world"}]:
bf.add(word)
assert bf.test(word) == 1, "Can't find recently added element"
"""Example how to use Classical Bloom Filter."""
from pdsa.membership.bloom_filter import BloomFilter
LOREM_IPSUM = (
"Lorem ipsum dolor sit amet, consectetur adipiscing elit."
" Mauris consequat leo ut vehicula placerat. In lacinia, nisl"
" id maximus auctor, sem elit interdum urna, at efficitur tellus"
" turpis at quam. Pellentesque eget iaculis turpis. Nam ac ligula"
" ut nunc porttitor pharetra in non lorem. In purus metus,"
" sollicitudin tristique sapien.")
if __name__ == '__main__':
bf = BloomFilter(80000, 4)
print(bf)
print("Bloom filter uses {} bytes in the memory".format(bf.sizeof()))
print("Filter contains approx. {} unique elements".format(bf.count()))
print("'Lorem' {} in the filter".format(
"is" if bf.test("Lorem") else "is not"))
words = set(LOREM_IPSUM.split())
for word in words:
bf.add(word.strip(" .,"))
print("Added {} words, in the filter approx. {} unique elements".format(
len(words), bf.count()))
print("'Lorem' {} in the filter".format(